# -*- Mode: Python; tab-width: 4 -*-

# ======================================================================
# Copyright 1997 by Sam Rushing
# 
#                         All Rights Reserved
# 
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby
# granted, provided that the above copyright notice appear in all
# copies and that both that copyright notice and this permission
# notice appear in supporting documentation, and that the name of Sam
# Rushing not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission.
# 
# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# ======================================================================

"""socket interface to unix syslog.
On Unix, there are usually two ways of getting to syslog: via a
local unix-domain socket, or via the TCP service.

Usually "/dev/log" is the unix domain socket.  This may be different
for other systems.

>>> my_client = syslog_client ('/dev/log')

Otherwise, just use the UDP version, port 514.

>>> my_client = syslog_client (('my_log_host', 514))

On win32, you will have to use the UDP version.  Note that
you can use this to log to other hosts (and indeed, multiple
hosts).

This module is not a drop-in replacement for the python
<syslog> extension module - the interface is different.

Usage:

>>> c = syslog_client()
>>> c = syslog_client ('/strange/non_standard_log_location')
>>> c = syslog_client (('other_host.com', 514))
>>> c.log ('testing', facility='local0', priority='debug')

"""

# TODO: support named-pipe syslog.
# [see ftp://sunsite.unc.edu/pub/Linux/system/Daemons/syslog-fifo.tar.z]

# from <linux/sys/syslog.h>:
# ===========================================================================
# priorities/facilities are encoded into a single 32-bit quantity, where the
# bottom 3 bits are the priority (0-7) and the top 28 bits are the facility
# (0-big number).  Both the priorities and the facilities map roughly
# one-to-one to strings in the syslogd(8) source code.  This mapping is
# included in this file.
#
# priorities (these are ordered)

LOG_EMERG		= 0		#  system is unusable 
LOG_ALERT		= 1		#  action must be taken immediately 
LOG_CRIT		= 2		#  critical conditions 
LOG_ERR			= 3		#  error conditions 
LOG_WARNING		= 4		#  warning conditions 
LOG_NOTICE		= 5		#  normal but significant condition 
LOG_INFO		= 6		#  informational 
LOG_DEBUG		= 7		#  debug-level messages 

#  facility codes 
LOG_KERN		= 0		#  kernel messages 
LOG_USER		= 1		#  random user-level messages 
LOG_MAIL		= 2		#  mail system 
LOG_DAEMON		= 3		#  system daemons 
LOG_AUTH		= 4		#  security/authorization messages 
LOG_SYSLOG		= 5		#  messages generated internally by syslogd 
LOG_LPR			= 6		#  line printer subsystem 
LOG_NEWS		= 7		#  network news subsystem 
LOG_UUCP		= 8		#  UUCP subsystem 
LOG_CRON		= 9		#  clock daemon 
LOG_AUTHPRIV	= 10	#  security/authorization messages (private) 

#  other codes through 15 reserved for system use 
LOG_LOCAL0		= 16		#  reserved for local use 
LOG_LOCAL1		= 17		#  reserved for local use 
LOG_LOCAL2		= 18		#  reserved for local use 
LOG_LOCAL3		= 19		#  reserved for local use 
LOG_LOCAL4		= 20		#  reserved for local use 
LOG_LOCAL5		= 21		#  reserved for local use 
LOG_LOCAL6		= 22		#  reserved for local use 
LOG_LOCAL7		= 23		#  reserved for local use 

priority_names = {
	"alert":	LOG_ALERT,
	"crit":		LOG_CRIT,
	"debug":	LOG_DEBUG,
	"emerg":	LOG_EMERG,
	"err":		LOG_ERR,
	"error":	LOG_ERR,		#  DEPRECATED 
	"info":		LOG_INFO,
	"notice":	LOG_NOTICE,
	"panic": 	LOG_EMERG,		#  DEPRECATED 
	"warn":		LOG_WARNING,		#  DEPRECATED 
	"warning":	LOG_WARNING,
	}

facility_names = {
	"auth":		LOG_AUTH,
	"authpriv":	LOG_AUTHPRIV,
	"cron": 	LOG_CRON,
	"daemon":	LOG_DAEMON,
	"kern":		LOG_KERN,
	"lpr":		LOG_LPR,
	"mail":		LOG_MAIL,
	"news":		LOG_NEWS,
	"security":	LOG_AUTH,		#  DEPRECATED 
	"syslog":	LOG_SYSLOG,
	"user":		LOG_USER,
	"uucp":		LOG_UUCP,
	"local0":	LOG_LOCAL0,
	"local1":	LOG_LOCAL1,
	"local2":	LOG_LOCAL2,
	"local3":	LOG_LOCAL3,
	"local4":	LOG_LOCAL4,
	"local5":	LOG_LOCAL5,
	"local6":	LOG_LOCAL6,
	"local7":	LOG_LOCAL7,
	}

import socket

class syslog_client:
	def __init__ (self, address='/dev/log'):
		self.address = address
		if type (address) == type(''):
			self.socket = socket.socket (socket.AF_UNIX, socket.SOCK_STREAM)
			self.socket.connect (address)
			self.unix = 1
		else:
			self.socket = socket.socket (socket.AF_INET, socket.SOCK_DGRAM)
			self.unix = 0

	# curious: when talking to the unix-domain '/dev/log' socket, a
	#   zero-terminator seems to be required.  this string is placed
	#   into a class variable so that it can be overridden if
	#   necessary.

	log_format_string = '<%d>%s\000'

	def log (self, message, facility=LOG_USER, priority=LOG_INFO):
		message = self.log_format_string % (
			self.encode_priority (facility, priority),
			message
			)
		if self.unix:
			self.socket.send (message)
		else:
			self.socket.sendto (message, self.address)

	def encode_priority (self, facility, priority):
		if type(facility) == type(''):
			facility = facility_names[facility]
		if type(priority) == type(''):
			priority = priority_names[priority]			
		return (facility<<3) | priority

	def close (self):
		if self.unix:
			self.socket.close()

